Anticoagulant 1,2,3,4,6-pentagalloyl-beta-D-glucopyranose isolated from geranium (Pelargonium inquinans Ait)

Geranium (Pelargonium inquinans Ait) leaves were extracted with 80% MeOH, and partitioned into n-hexane, ethyl acetate, BuOH and H2O to isolate the anticoagulant principles. The EtOAc fraction was found to be the most active, and was further purified using silica and octadecylsilane column chromatography employing a bioassay-guided fractionation method. The active compound was isolated and identified as 1,2,3,4,6-pentagalloyl-beta-D-glucopyranose (PGG) (compound I). The isolated anticoagulant significantly prolonged the activated partial thrombin time (APTT) and thrombin time (TT) using normal human plasma. One microgram of 1,2,3,4,6-pentagalloyl-beta-D-glucopyranose showed 0.063 heparin units in the APTT and 2.73 heparin units in the TT for anti-thrombosis. This is the first report of the isolation of PGG from geranium plants.